Cosmic rays, beryllium from

Fig. 9.8. Trend of beryllium abundance with metallicity compared to predictions from two models (a) CRS denotes cosmic-ray acceleration in superbubbles rich in iron and oxygen as predicted from theoretical supernova yields (in this case those of Tsujimoto and Shigeyama 1998) and (b) CRI denoting cosmic rays accelerated from the general interstellar medium. The density dependence comes from its influence on the delay in the deposition of the synthesized Be. Virtually identical results were obtained using the yields from Woosley and Weaver (1995). After Ramaty et al. (2000).

SNII events alone explain the observed solar abundance distribution between oxygen and chromium. This can be taken as a major theoretical achievement. Complementary sources of hydrogen, helium, lithium, beryllium, boron, carbon and nitrogen are required, and these have been identified. They are the Big Bang, cosmic rays and intermediate-mass stars. Around iron and a little beyond, we must invoke a contribution from type la supernovas (Pig. 8.5). These must be included to reproduce the evolution of iron abundances, a fact which suggests... 

It is appropriate to begin this lecture with a diagram from the review of Shapiro Silberberg, 1970, which compares the abundances of elements in the cosmic radiation with solar system abundances. This classic measurement is one of the foundations of cosmic-ray physics. The elements lithium, beryllium and boron are quite abundant among cosmic rays even though they constitute only a tiny fraction of the material in the solar system and the interstellar medium. This fact is understood largely as the result of spallation of the... 

Lead-210 formed in the atmosphere via Rn which diffuses from the earth s surface is adsorbed to aerosols or dust particles, and gradually deposits on to the earth s surface. It is not in radioequilibrium with Ra, and is referred to as unsupported Pb . Thus, after being deposited, atmospherically derived Pb can be distinguished as an excess of associated Ra, and can be used as a radioactive tracer. An extensive discussion of the origin and the scientific applications of radioactive lead has been provided by Wise (1980). Beryllium-7 is formed by cosmic ray spallation of... 

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